Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Nomeie o país para o dólar americano.
 ###Tabelas: CREATE TABLE main_issuers (main_issuers_id AUTO_INCREMENT PRIMARY KEY, Currency VARCHAR, Country VARCHAR, Generic Name or Nickname VARCHAR, Rating ( S&P / Moodys ) VARCHAR, Negotiable debt at mid-2005 ( US dollar bn equivalent) INT, Government financial liabilities as % of GDP (end 2003 - source : OECD ) VARCHAR, Issuer VARCHAR, Internet site VARCHAR) CREATE TABLE player_statistics (player_statistics_id AUTO_INCREMENT PRIMARY KEY, No. INT, Player VARCHAR, League Apps INT, League Goals INT, Cup Apps INT, Cup Goals INT, Total Apps INT, Total Goals INT, YC INT, RC INT) CREATE TABLE ro_ro_passenger_ships (ro_ro_passenger_ships_id AUTO_INCREMENT PRIMARY KEY, Ship name VARCHAR, Year INT, Length VARCHAR, Width VARCHAR, Passengers INT, Vessels INT, Speed INT) CREATE TABLE 2011_fixtures_and_results (2011_fixtures_and_results_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, Tournament VARCHAR, Location VARCHAR, Home team VARCHAR, Score VARCHAR, Away team VARCHAR) CREATE TABLE major_agricultural_products (major_agricultural_products_id AUTO_INCREMENT PRIMARY KEY, Commodity VARCHAR, 2001-02 INT, 2002-03 INT, 2003-04 INT, 2004-05 INT, 2005-06 INT, 2006-07 INT)  
SELECT Country FROM main_issuers WHERE Currency = US dollar